Molecular mechanisms of action associated with protein secretion were studied in parotid gland acinar cells. Standard biochemical, immunological, morphological methods, and new experimental techniques such as photoaffinity labelling (8-azido cyclic [32P]-AMP), enzyme linked immunosorbent antibody technique (ELISA) and microscopic examination (LM and EM) of cells and subcellular fractions were part of the experimental design. Computer application for a data base analysis employed largely RS1 and graphics (GRAPH 1) software. Cellular responses to receptor interactions of parotid cells with Beta-agonists were studied using measurement of cyclic AMP-dependent protein phosphorylation as an index in both extranuclear as well as in chromatin-bound nonhistone nuclear protein cell fractions. Redistribution of protein kinase isozymes and changes in gene expression occur after stimulation with isoproterenol. Cyclic AMP-binding proteins (cAMP PK regulatory, R1 subunits) have been identified in human and in rat saliva. Translatable (poly A) mRNA has been isolated from rat parotid tissue for determining stimulation-induced gene regulation of secretory protein synthesis using specific immunological reagents.